SU1504249A1 - Method of pretreatment of cellulose-containing initial material for enzymic hydrolysis - Google Patents

Abstract

The invention relates to the hydrolysis industry, in particular to methods for the pretreatment of cellulosic raw materials for the enzymatic production of sugars, and can be used in the microbiological industry, the food and feed mill industries. The purpose of the invention is to increase the degree of hydrolizability of the raw material by reducing the lignin content. The method is carried out as follows. Prepare an aqueous suspension with a solid phase concentration (1:15) - (1:20) and process it with a constant electric current with a voltage across the electrodes of 50-100 V at a current density of 0.1-1 A / dm ² in the presence of 2- 8% H ₂ O ₂ in an acidic environment. Acetic acid in the amount of 1-5% is used for acidification, and sulfuric acid can be additionally added in an amount of 0.1-3%. The proposed method of preprocessing cellulosic raw materials reduces the duration of the preprocessing process as compared with the prototype from 6.5 hours or more to 20-60 minutes and provides an increase in the degree of hydrolysis by 12-20%. 1 hp f-ly.

Description

The invention relates to the hydrolysis industry, in particular to methods for the pretreatment of cellulose-containing raw materials for the enzymatic production of sugars, and can be used in the microbiological, food and feed industries.

The purpose of the invention is to increase the degree of hydrolizability of the raw material by reducing the lignin content.

The method is carried out as follows.

Preparing a suspension of cellulosic raw materials with a concentration of (I: 15) - (i: 20), RNOSYAT 1-5% vinegar: ioy

acids and 2-8% and carry out the treatment by direct electric current with a voltage on the electrodes of 50-100 V and a current density of 0.1-1 A / dm. Processing time 20-60 minutes depending on the type of raw material.

For various types of raw materials, acidification is carried out with either acetic acid in an amount of 1-5%, or its combination with sulfuric acid in an amount of 0.1-3%.

The optimum value of the amount of acid added depends on the chemical composition of the raw material, is chosen experimentally in each particular case, and varies within the specified limits.

The introduction of sulfuric acid within the specified limits, along with acetic acid, all other things being equal, of preprocessing makes it possible to reduce the lignin content by 0.5–3% and increase the degree of dryness of the raw material by 2–6%.

Example 1. An aqueous JQ suspension is prepared from paper dust with a lignin content of 12.5% at a ratio of 1:15, 1% CHjCCTOH is added, 2% and a constant electric treatment is carried out. The content of lignin after pretreatment is 4.2%. The degree of hydrolysis is 55%.

Example 7. A slurry of chopped straw is subjected to preprocessing with a constant electric current at a voltage on the electrodes of 100 V, current density of 1 A / dm, in the presence of 8%, 3% CH, COOH and 3% H-Go. The degree of hydrolysis is 68%.

The upper limiting concentration ratio in water is 1:15, since when using more gus

kim current with voltage of 50 V and dense suspensions brewing

35

current of 0.1 A / dm for 20 min. The content of lignin in the raw material after preprocessing 6%. The degree of hydrolysis with complex enzyme preparations Celoreverin P10X and Pectofoetidin P10X 20 is 49%, in the control without pretreatment - 37%, with mechanical treatment on a vibrating mill - 44%, with preprocessing according to the prototype - 34%.

Example 2. A paper dust suspension is prepared as in Example 1 and will be pretreated at a voltage of 100 V and a current density of 1 A / dm. 1%, 2% H, 0j are introduced into the reaction medium. Duration of treatment of DL is 20 min. The lignin content after processing is 4.5%. The degree of hydrolysis is 52%.

Example 3. A paper dust suspension of 1:20 is subjected to Treatment with a constant electric current with a voltage of 50 V, current density of 1 A / dm in the presence of 5% of 1 TCO, 1% of CH. The content of lignin after processing was 4.6%. The degree of hydrolysis of 55.5% .Q

Example 4. The suspension of paper dust 1:15 is subjected to preprocessing by direct electric current at a voltage on the electrodes of 50 V and a current density of 0.5 A / dm in the presence of 5%, 4%. The content of lignin after processing was 3.7%. The degree of hydrolysis is 56%.

Example 5. The suspension of paper dust is subjected to preprocessing by direct electric current at a voltage on the electrodes of 50 V and a current density of 0.1 A / dm. Hydronic module 1:15. The pretreatment is carried out in the presence of 5%, 5% CHjCOOH, 1%. The degree of hydrolysis of 54%.

Example 6. Carried out analogously to example 5. Content.

substrate on electrodes with irreversible chemical changes. The lower limit of 1:20 is determined by economic considerations (productivity and energy intensity per unit of raw materials, as well as a decrease in the system's storage capacity.

Claims (2)

1. Method of pretreatment of cellulosic raw materials for fer , mentally hydrolysis, including the preparation of an aqueous suspension of the raw material followed by electrochemical processing, characterized in that, in order to increase the degree of hydrolizability of the raw material by reducing the lignin content, the concentration of the solid phase in the aqueous suspension is (1:15) - (1:20 ), and the treatment of the aqueous suspension is carried out at a voltage on the electrodes of 50–100 V and a current density of 0.1–1 A / dm for 20–60 min, with 1–5% acetic acid being introduced into the suspension and 2-8% hydrogen peroxide. five 0 ABOUT Q substrate on electrodes with irreversible chemical changes. The lower limit of 1:20 is determined by economic considerations (productivity and energy intensity per unit of raw materials, as well as a decrease in the system's storage capacity. With a voltage across the electrodes of 50-100 V, a current density of 0.1-1 A / dm, 5 processing times of 20-60 minutes, in an acidic medium (1-5% acetic acid or in combination with 0.1-3% sulfuric acid), the peroxide is rapidly decomposed to active oxygen (under normal conditions, this process is difficult and slow, even at elevated temperatures) and efficient oxidation of lignin, while the processing of the substrate under these electrolysis modes reduces the crystallinity of cellulose. As a result of processing by the proposed method, the degree of hydrolizability of the raw material increases by 12–20%, productivity increases due to the use of concentrated suspensions. Invention Formula 1. A method of pretreatment of cellulosic raw materials for ferments, of mentally hydrolysis, including the preparation of an aqueous suspension of the raw material followed by electrochemical treatment, characterized in that, in order to increase the degree of hydrolysis of the raw material by reducing the lignin content, the concentration of the solid phase in the aqueous suspension is (1 : 15) - (1:20), and the treatment of the aqueous suspension was carried out at a voltage on the electrodes of 50-100 V and a current density of 0.1-1 A / dm for 20- 60 min, while 1 -5% acetic acid and 2-8% batch si hydrogen. 5I5042A9 2. The method according to p. 1, the difference is introduced additionally sulfuric acid KZ w and so that the suspension in an amount of 0.1-3%.